Methods for producing thin-film layers and microsystems having thin-film layers

ABSTRACT

A method for producing a thin-film layer includes providing a layer stack on a carrier substrate, wherein the layer stack includes a carrier layer and a sacrificial layer, and wherein the sacrificial layer includes areas in which the carrier layer is exposed. The method includes providing the thin-film layer on the layer stack, such that the thin-film layer bears on the sacrificial layer and, in the areas of the sacrificial layer in which the carrier layer is exposed, against the carrier layer. The method includes at least partly removing the sacrificial layer from the thin-film layer in order to eliminate a contact between the thin-film layer and the sacrificial layer in some areas. The method also includes detaching the thin-film layer from the carrier layer.

This application claims the benefit of German Application Nos.102018201931.2, filed on Feb. 7, 2018 and 102018214017.0, filed Aug. 20,2018, which applications are hereby incorporated herein by reference.

TECHNICAL FIELD

Exemplary embodiments relate to a method for producing a thin-filmlayer. Further exemplary embodiments relate to a method for producing amicrosystem having a thin-film layer. Some exemplary embodiments relateto a method for zero force debonding of a thin device by means ofhigh/low force areas.

BACKGROUND

Wafers having a thickness of less than 100 μm cannot be handled usingstandard tools. Therefore, these wafers are mounted onto a carrierwafer. An entire process chain for handling thin wafers has beendeveloped by industry. However, very thin and fragile structures can bedamaged by the standard thin-wafer processing steps.

SUMMARY

Exemplary embodiments provide a method for producing a thin-film layer(or a microsystem having a thin-film layer). The method comprises a stepof providing a carrier substrate. Furthermore, the method comprises astep of providing a layer stack on the carrier substrate, wherein thelayer stack comprises a carrier layer and a sacrificial layer, whereinthe sacrificial layer comprises areas in which the carrier layer isexposed. Furthermore, the method comprises a step of providing thethin-film layer on the layer stack, such that the thin-film layer bearson the sacrificial layer and, in the areas of the sacrificial layer inwhich the carrier layer is exposed, against the carrier layer.Furthermore, the method comprises a step of at least partly removing thesacrificial layer proceeding from the thin-film layer in order toeliminate a contact between the thin-film layer and the sacrificiallayer at least in areas. Furthermore, the method comprises a step ofdetaching the thin-film layer from the carrier layer.

In exemplary embodiments, the thin-film layer can have a thickness ofless than 100 μm (or 70 μm, or 50 μm, or 30 μm, or 20 μm, or 10 μm, or 5μm).

In exemplary embodiments, the thin-film layer can be a membrane or afilter, for example of a microsystem (MEMS=microelectromechanicalsystem).

In exemplary embodiments, the thin-film layer can be a polyimide layeror a combination of polyimide layer and SU-8 layer.

In exemplary embodiments, an exposed surface area of the carrier layer(=surface area of the carrier layer which is exposed in the areas of thesacrificial layer, or surface area of the carrier layer that is notcovered by the sacrificial layer) can occupy for example less than 40%(or 30%, or 20%, or 15%, or 10%, or 5%) of a total surface area of thecarrier layer.

In exemplary embodiments, detaching the thin-film layer can comprise thefollowing steps: (1) providing an at least single-sided-adhesivetransfer carrier layer on the thin-film layer such that the thin-filmlayer adheres to the adhesion layer, and (2) detaching the transfercarrier layer in order to detach the thin-film layer adhering to thetransfer carrier layer from the carrier layer.

In exemplary embodiments, the transfer carrier layer can comprise anadhesive layer on a side facing the thin-film layer.

In exemplary embodiments, the method can furthermore comprise a step ofstructuring the thin-film layer before detaching the thin-film layer.

In exemplary embodiments, the method can furthermore comprise a step ofproducing at least one microsystem on the thin-film layer, whereinduring the process of detaching the thin-film layer, the at least onemicrosystem is detached together with the thin-film layer.

In exemplary embodiments, the thin-film layer can be part of the atleast one microsystem.

In exemplary embodiments, providing the layer stack can comprise thefollowing steps: (1) providing the carrier layer on the carriersubstrate, (2) providing the sacrificial layer on the carrier layer, and(3) opening the sacrificial layer in areas as far as the carrier layerin order to obtain the areas in which the carrier layer is exposed.

In exemplary embodiments, the areas in which the carrier layer isexposed can be holes.

In exemplary embodiments, the holes can have a diameter of 7 μm.

In exemplary embodiments, the sacrificial layer can be a secondsacrificial layer, wherein providing the layer stack can comprise thefollowing steps: (1) providing a first sacrificial layer on the carriersubstrate, wherein the first sacrificial layer comprises elevations, (2)providing the carrier layer on the first sacrificial layer, (3)providing the second sacrificial layer on the carrier layer, and (4) atleast partly removing the second sacrificial layer as far as the carrierlayer on the elevations of the first sacrificial layer in order toobtain the areas in which the carrier layer is exposed.

In exemplary embodiments, the elevations can have a diameter of 20 μm orless.

In exemplary embodiments, the sacrificial layer can comprise siliconoxide, aluminum, titanium or copper.

In exemplary embodiments, the carrier layer can comprise nitride orsilicon nitride.

Further exemplary embodiments provide a method for producing a thin-filmlayer. The method comprises a step of providing a carrier substrate.Furthermore, the method comprises a step of providing a sacrificiallayer on the carrier substrate. Furthermore, the method comprises a stepof providing the thin-film layer on the sacrificial layer. Furthermore,the method comprises a step of structuring the thin-film layer in orderto obtain in a lateral plane of the thin-film layer an inner area of thethin-film layer which is at least partly surrounded by an outer area ofthe thin-film layer, wherein during the process of structuring thethin-film layer, at least one opening arises in the thin-film layerwhich at least partially frees the inner area of the thin-film layer inthe lateral plane, wherein during the process of structuring thethin-film layer, at least two webs remain which extend in a lateralplane of the thin-film layer from the outer area of the thin-film layerinto the opening in the direction of the inner area of the thin-filmlayer. Furthermore, the method comprises a step of at least partlyremoving the sacrificial layer proceeding from the thin-film layer inorder to eliminate a contact between the inner area of the thin-filmlayer and the sacrificial layer. Furthermore, the method comprises astep of detaching the inner area of the thin-film layer from the outerarea of the thin-film layer.

In exemplary embodiments, the thin-film layer can have a thickness ofless than 100 μm (or 70 μm, or 50 μm, or 30 μm, or 20 μm, or 10 μm, or 5μm).

In exemplary embodiments, the thin-film layer or the inner area of thethin-film layer can be a membrane or a filter, for example a microsystem(MEMS=microelectromechanical system).

In exemplary embodiments, the thin-film layer can be a polyimide layeror a combination of polyimide layer and SU-8 layer.

In exemplary embodiments, the outer area of the thin-film layer which atleast partly surrounds the inner area of the thin-film layer can form aframe structure. By way of example, the frame structure can completelysurround the inner area of the thin-film layer. Of course, the framestructure can also only partly surround the inner area of the thin-filmlayer, for example at opposite sides of the inner area of the thin-filmlayer.

In exemplary embodiments, during the process of structuring thethin-film layer, the inner area of the thin-film layer can be freed inthe lateral plane of the thin-film layer, wherein after structuring thethin-film layer, a carrier layer can be provided (e.g. deposited) on thethin-film layer and structured in order to obtain a carrier structureextending over the inner area of the thin-film layer and at least partlyover the webs, such that the carrier structure connects the inner areaof the thin-film layer to the webs.

By way of example, the inner area of the thin-film layer can becompletely separated from the outer area of the thin-film layer in alateral plane of the thin-film layer. During the process of structuringthe thin-film layer, an opening can thus form in the thin-film layerbetween the inner area of the thin-film layer and the outer area of thethin-film layer, wherein the opening completely surrounds the inner areaof the thin-film layer. Since the at least two webs proceeding from theouter area of the thin-film layer project into the opening in thedirection of the thin-film layer but do not reach the inner area of thethin-film layer (i.e. are not connected to the inner area of thethin-film layer), it is possible to provide on the inner area of thethin-film layer a carrier structure extending as far as the at least twowebs, such that the inner area of the thin-film layer is connected tothe at least two webs by way of the carrier structure, such that afterremoving the sacrificial layer below the inner area of the thin-filmlayer, e.g. by undercutting, the inner area of the thin-film layer iscarried by the at least two webs of the outer area of the thin-filmlayer by way of the carrier structure.

In exemplary embodiments, after at least partly removing the sacrificiallayer, the inner area of the thin-film layer can be carried by the atleast two webs of the outer area of the thin-film layer by way of thecarrier structure.

By way of example, the carrier structure can extend at least partly overthe at least two webs, such that the carrier structure bears on the atleast two webs of the outer area of the thin-film layer.

In exemplary embodiments, the carrier layer, after the process ofstructuring the thin-film layer, can be provided on the thin-film layerand on the sacrificial layer in the region of the opening of thethin-film layer.

By way of example, the carrier structure can thus extend at least partlyover the opening between the inner area of the thin-film layer and theouter area of the thin-film layer, e.g. between the areas of the webs onwhich the carrier layer bears.

In exemplary embodiments, the sacrificial layer proceeding from thethin-film layer can be at least partly removed by etching in order toeliminate the contact between the inner area of the thin-film layer andthe sacrificial layer.

By way of example, the sacrificial layer can be undercut in the areabelow the inner area of the thin-film layer. During the etching process,a top side of the inner area of the thin-film layer can be protected bythe carrier structure, such that the inner area of the thin-film layeris undercut proceeding from the opening between the inner area of thethin-film layer and the outer area of the thin-film layer.

In exemplary embodiments, the carrier layer (or carrier structure)and/or the sacrificial layer can have in each case a higher etching ratethan the thin-film layer.

In exemplary embodiments, during the process of detaching the inner areaof the thin-film layer, the carrier structure can be detached togetherwith the inner area of the thin-film layer.

In exemplary embodiments, the carrier layer can have a thickness of morethan 30 μm (or 40 μm, or 50 μm, or 60 μm). By way of example, thethickness of the carrier layer can be in the range of 40 μm to 100 μm.

In exemplary embodiments, the carrier layer can be a polymer layer, suchas e.g. an SU-8 layer.

In exemplary embodiments, during the process of structuring thethin-film layer, at least two openings can arise in the thin-film layerwhich partially (i.e. not completely) free the inner area of thethin-film layer in the lateral plane, wherein the at least two websremain between the openings and connect the inner area of the thin-filmlayer to the outer area of the thin-film layer.

By way of example, during the process of structuring the thin-filmlayer, the inner area of the thin-film layer can be only partlyseparated from the outer area of the thin-film layer, that is to saythat although openings arise between the inner area of the thin-filmlayer and the outer area of the thin-film layer, these are stillconnected by thin webs, such that after removing the sacrificial layerbelow the inner area of the thin-film layer, e.g. by undercutting, theinner area of the thin-film layer is carried by the at least two webs ofthe outer area of the thin-film layer.

In exemplary embodiments, after at least partly removing the sacrificiallayer, the inner area of the thin-film layer can be carried by the atleast two webs.

In exemplary embodiments, during the process of detaching the inner areaof the thin-film layer from the outer area of the thin-film layer, theat least two webs can break.

In exemplary embodiments, the at least two webs can in each casecomprise a tapering area. The tapering areas of the at least two webscan be predetermined breaking locations, for example, which define thelocations at which the at least two webs break during the process ofdetaching the inner area of the thin-film layer.

In exemplary embodiments, detaching the thin-film layer can comprise thefollowing steps: (1) providing an at least single-sided-adhesivetransfer carrier layer on the inner area of the thin-film layer (or onthe carrier structure on the inner area of the thin-film layer); and (2)detaching the transfer carrier layer in order to detach the inner areaof the thin-film layer adhering to the transfer carrier layer (or thecarrier structure, and thus also the inner area of the thin-film layer,adhering to the transfer carrier layer) from the outer area of thethin-film layer.

In exemplary embodiments, the transfer carrier layer can comprise anadhesive layer on a side facing the thin-film layer.

In exemplary embodiments, the method can comprise a step of producing atleast one microsystem on the inner area of the thin-film layer, whereinduring the process of detaching the inner area of the thin-film layer,the at least one microsystem is detached together with the inner area ofthe thin-film layer.

By way of example, the microsystem can be produced before providing thecarrier layer, wherein after the at least one microsystem has beenproduced, the carrier layer is provided on the at least one microsystem,such that the microsystem is protected by the carrier layer.

In exemplary embodiments, the inner area of the thin-film layer can bepart of the at least one microsystem.

In exemplary embodiments, the sacrificial layer can comprise siliconoxide.

In exemplary embodiments, the method can furthermore comprise a step ofproviding an anti-sticking structure on the carrier substrate, whereinthe sacrificial layer is provided on the carrier substrate and theanti-sticking structure, wherein the inner area of the thin-film layerthat results during the process of structuring the thin-film layer isarranged adjacent to the anti-sticking structure, wherein during theprocess of at least partly removing the sacrificial layer, theanti-sticking structure is at least partly exposed, wherein during theprocess of detaching the inner area of the thin-film layer, the innerarea of the thin-film layer is lifted off from the anti-stickingstructure.

In exemplary embodiments, the anti-sticking structure can compriseelevations extending in at least one lateral dimension along a surfaceof the carrier substrate.

In exemplary embodiments, the elevations can have a width of less than 2μm.

In exemplary embodiments, the elevations can extend in one lateraldimension, wherein the elevations, in a lateral plane of same, formlines.

In exemplary embodiments, the elevations can extend in two lateraldimensions, wherein the elevations, in a lateral plane of same, formcircles.

In exemplary embodiments, the inner area of the thin-film layer cancomprise a lattice structure having hexagonal openings, wherein thelattice structure forms a particle barrier, a filter or a membrane.

In exemplary embodiments, the method can furthermore comprise a step ofproviding a further anti-sticking structure on an outer area of thethin-film layer or on a layer arranged thereon, wherein detaching thethin-film layer can comprise the following steps: providing an at leastsingle-sided-adhesive transfer carrier layer on the inner area of thethin-film layer and the further anti-sticking structure; detaching thetransfer carrier layer in order to detach the inner area of thethin-film layer adhering to the transfer carrier layer from the outerarea of the thin-film layer.

In exemplary embodiments, the method can furthermore comprise a step ofproviding a wafer and a step of mounting the carrier substrate on thewafer before detaching the inner area of the thin-film layer from theouter area of the thin-film layer.

In exemplary embodiments, the inner area of the thin-film layer can bedetached from the outer area of the thin-film layer by means of apick-and-place method.

By way of example, the anti-sticking structure can be embedded in oxidebefore the etching-free process. During the oxide etch, the thin-filmlayer (e.g. filter structure) can come into contact with theanti-sticking structure.

By way of example, the anti-sticking structure can be constructed as aline in order that the thin-film layer (e.g. filter structure) cannotfall down.

By way of example, the thin-film layer (e.g. filter structure) can haveonly slight contact with the anti-sticking structure, such that duringthe process of detaching the inner area of the thin-film layer, theinner area of the thin-film layer is lifted off from the anti-stickingstructure.

Further exemplary embodiments provide a method for producing a thin-filmlayer. The method comprises a step of providing a carrier substrate.Furthermore, the method comprises a step of providing an anti-stickingstructure on the carrier substrate. Furthermore, the method comprises astep of providing a sacrificial layer on the anti-sticking structure andthe carrier substrate. Furthermore, the method comprises a step ofproviding the thin-film layer on the sacrificial layer. Furthermore, themethod comprises a step of structuring the thin-film layer in order toobtain in a lateral plane of the thin-film layer an inner area of thethin-film layer which is at least partly surrounded by an outer area ofthe thin-film layer and is arranged in a vertical direction above theanti-sticking structure, wherein during the process of structuring thethin-film layer, at least one opening arises in the thin-film layerwhich at least partially frees the inner area of the thin-film layer inthe lateral plane, wherein during the process of structuring thethin-film layer, at least two webs remain which extend in a lateralplane of the thin-film layer from the outer area of the thin-film layerinto the opening in the direction of the inner area of the thin-filmlayer. Furthermore, the method comprises a step of at least partlyremoving the sacrificial layer proceeding from the thin-film layer inorder to eliminate a contact between the inner area of the thin-filmlayer and the sacrificial layer, wherein during the process of at leastpartly removing the sacrificial layer, the anti-sticking structure is atleast partly exposed.

In exemplary embodiments, the anti-sticking structure serves to ensurethat the thin-film layer (e.g. filter) does not stick to the support,while the webs hold the thin-film layer (e.g. filter) in position untilthe latter is lifted off e.g. with a tape.

In exemplary embodiments, the anti-sticking structure can compriseelevations extending in at least one lateral dimension along a surfaceof the carrier substrate.

In exemplary embodiments, the elevations can have a width of less than 2μm.

In exemplary embodiments, the elevations can extend in one lateraldimension, wherein the elevations, in a lateral plane of same, formlines.

In exemplary embodiments, the elevations can extend in two lateraldimensions, wherein the elevations, in a lateral plane of same, formcircles.

In exemplary embodiments, the inner area of the thin-film layer cancomprise a lattice structure having hexagonal openings, wherein thelattice structure forms a particle barrier, a filter or a membrane.

In exemplary embodiments, the method can furthermore comprise a step ofproviding a further anti-sticking structure on an outer area of thethin-film layer or on a layer arranged thereon, a step of providing anat least single-sided-adhesive transfer carrier layer on the inner areaof the thin-film layer and the further anti-sticking structure, and astep of detaching the transfer carrier layer in order to detach theinner area of the thin-film layer adhering to the transfer carrier layerfrom the outer area of the thin-film layer.

In exemplary embodiments, the method can furthermore comprise a step ofproviding a wafer and mounting the carrier substrate on the wafer.

In exemplary embodiments, the method can furthermore comprise a step oflifting off (or detaching) the inner area of the thin-film layer fromthe outer area of the thin-film layer e.g. by means of a pick-and-placemethod.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention are described in greaterdetail with reference to the accompanying figures, in which:

FIG. 1 shows a flow diagram of a method for producing a thin-film layer;

FIG. 2 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingthe carrier substrate;

FIG. 3 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of providing thecarrier layer on the carrier substrate;

FIG. 4 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of providing astructured sacrificial layer on the carrier layer;

FIG. 5 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providing athin-film layer on the structured sacrificial layer and, in the areas ofthe sacrificial layer in which the carrier layer is exposed, on thecarrier layer;

FIG. 6 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of at leastpartly removing the sacrificial layer proceeding from the thin-filmlayer in order to eliminate a contact between the thin-film layer andthe sacrificial layer at least in areas, such that the thin-film layeris carried principally only by the carrier layer;

FIG. 7 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingan at least single-sided-adhesive transfer carrier layer on thethin-film layer, such that the thin-film layer adheres to the transfercarrier layer;

FIG. 8 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of detachingthe thin-film layer from the carrier layer;

FIG. 9 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingthe carrier substrate;

FIG. 10 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of providing afirst sacrificial layer on the carrier substrate;

FIG. 11 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of structuringthe first sacrificial layer;

FIG. 12 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of providing thecarrier layer on the first sacrificial layer;

FIG. 13 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of providing thesecond sacrificial layer on the carrier layer;

FIG. 14 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of at leastpartly removing the second sacrificial layer as far as the carrier layeron the elevations of the first sacrificial layer in order to obtain theareas in which the carrier layer is exposed;

FIG. 15 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providing athin-film layer on the structured sacrificial layer and, in the areas ofthe sacrificial layer emits the carrier layer in which is exposed, onthe carrier layer;

FIG. 16 shows a schematic sectional view of an intermediate product ofthe method for producing after an optional step of producingmicrosystems on the structured thin-film layer, such that the thin-filmlayer is part of the microsystems;

FIG. 17 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of at leastpartly removing the sacrificial layer proceeding from the thin-filmlayer in order to eliminate a contact between the thin-film layer andthe sacrificial layer at least in areas, such that the thin-film layeris carried principally only by the carrier layer;

FIG. 18 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingan at least single-sided-adhesive transfer carrier layer on thethin-film layer, such that the thin-film layer adheres to the transfercarrier layer;

FIG. 19 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of detachingthe thin-film layer from the carrier layer;

FIG. 20 shows a flow diagram of a method for producing a thin-filmlayer;

FIG. 21 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingthe carrier substrate;

FIG. 22 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingthe sacrificial layer on the carrier substrate;

FIG. 23 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingthe thin-film layer on the sacrificial layer and after the step ofstructuring the thin-film layer;

FIG. 24 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of at leastpartly removing the sacrificial layer proceeding from the thin-filmlayer in order to eliminate a contact between the inner area of thethin-film layer and the sacrificial layer;

FIG. 25 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingan at least single-sided-adhesive transfer carrier layer on thethin-film layer, such that the inner area of the thin-film layer adheresto the transfer carrier layer;

FIG. 26 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of detachingthe transfer carrier layer in order to detach the inner area of thethin-film layer adhering to the transfer carrier layer from the outerarea of the thin-film layer;

FIG. 27a shows a schematic plan view of the thin-film layer after thestep of structuring the thin-film layer and the step of providing thecarrier structure;

FIG. 27b shows a schematic plan view of the outer area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 27c shows a schematic plan view of the inner area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 28a shows a schematic plan view of the thin-film layer after thestep of structuring the thin-film layer and the step of providing thecarrier structure;

FIG. 28b shows a schematic plan view of the outer area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 28c shows a schematic plan view of the inner area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 29a shows a schematic plan view of the thin-film layer after thestep of structuring the thin-film layer and the step of providing thecarrier structure;

FIG. 29b shows a schematic plan view of the outer area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 29c shows a schematic plan view of the inner area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 30a shows a schematic plan view of the thin-film layer after thestep of structuring the thin-film layer and the step of providing thecarrier structure;

FIG. 30b shows a schematic plan view of the outer area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 30c shows a schematic plan view of the inner area of the thin-filmlayer after the step of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer;

FIG. 31 shows a schematic plan view of the thin-film layer after thestep of structuring the thin-film layer and the step of providing thecarrier structure;

FIG. 32 shows a recording (e.g. scanning electron microscope recording)of a thin-film layer and of an anti-sticking structure having anelevation extending in one lateral dimension;

FIG. 33 shows a microscope recording of the thin-film layer before thestep of providing the carrier structure;

FIG. 34 shows a schematic sectional view of the thin-film layer and aschematic plan view of the thin-film layer, wherein the inner area ofthe thin-film layer has a lattice structure having hexagonal openings,wherein the inner area of the thin-film layer is carried by the outerarea of the thin-film layer;

FIG. 35 shows a flow diagram of a method for producing a thin-filmlayer;

FIG. 36 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the steps of providingthe carrier substrate, providing the anti-sticking structure on thecarrier substrate and providing the sacrificial layer on theanti-sticking structure and the carrier substrate;

FIG. 37 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingthe thin-film layer on the sacrificial layer and after the step ofstructuring the thin-film layer;

FIG. 38 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of at leastpartly removing the sacrificial layer proceeding from the thin-filmlayer in order to eliminate a contact between the inner area of thethin-film layer and the sacrificial layer;

FIG. 39 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingan at least single-sided-adhesive transfer carrier layer on thethin-film layer, such that the inner area of the thin-film layer adheresto the transfer carrier layer;

FIG. 40 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of detachingthe transfer carrier layer in order to detach the inner area of thethin-film layer adhering to the transfer carrier layer from the outerarea of the thin-film layer;

FIG. 41 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the steps of providingthe carrier substrate, providing the anti-sticking structure on thecarrier substrate and providing the sacrificial layer on theanti-sticking structure and the carrier substrate;

FIG. 42 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of providingthe thin-film layer on the sacrificial layer and after the step ofstructuring the thin-film layer;

FIG. 43 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after the step of at leastpartly removing the sacrificial layer proceeding from the thin-filmlayer in order to eliminate a contact between the inner area of thethin-film layer and the sacrificial layer;

FIG. 44 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of providing awafer and mounting the carrier substrate on the wafer before detachingthe inner area of the thin-film layer from the outer area of thethin-film layer;

FIG. 45 shows a schematic sectional view of an intermediate product ofthe method for producing a thin-film layer after a step of detaching theinner area of the thin-film layer from the outer area of the thin-filmlayer by means of a pick-and-place method; and

FIG. 46 shows a schematic plan view of the thin-film layer after thestep of structuring the thin-film layer and the step of providing thecarrier structure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following description of the exemplary embodiments of the presentinvention, in the figures identical or identically acting elements areprovided with the same reference sign, and so the description thereof ismutually interchangeable.

FIG. 1 shows a flow diagram of a method 100 for producing a thin-filmlayer. The method 100 comprises a step 102 of providing a carriersubstrate. Furthermore, the method 100 comprises a step 104 of providinga layer stack on the carrier substrate, wherein the layer stackcomprises a carrier layer and a sacrificial layer, wherein thesacrificial layer comprises areas in which the carrier layer is exposed.Furthermore, the method 100 comprises a step 106 of providing thethin-film layer on the layer stack, such that the thin-film layer bearson the sacrificial layer and, in the areas of the sacrificial layer inwhich the carrier layer is exposed, against the carrier layer.Furthermore, the method 100 comprises a step 108 of at least partlyremoving the sacrificial layer proceeding from the thin-film layer inorder to eliminate a contact between the thin-film layer and thesacrificial layer at least in areas. Furthermore, the method 100comprises a step no of detaching the thin-film layer from the carrierlayer.

Exemplary embodiments of the method 100 are described in detail belowwith reference to FIGS. 2 to 19, which show schematic sectional views ofintermediate products of the production of a thin-film layer after thevarious method steps. In detail, a first exemplary embodiment isdescribed with reference to FIGS. 2 to 8, and a second exemplaryembodiment with reference to FIGS. 9 to 19, wherein the two exemplaryembodiments differ in particular in the production of the layer stackcomprising the carrier layer and the sacrificial layer.

FIG. 2 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 102 ofproviding the carrier substrate 120. The carrier substrate 120 can befor example a semiconductor substrate or semiconductor wafer, such ase.g. a silicon substrate or silicon wafer.

With reference to FIGS. 2 and 3, a more detailed description is givenbelow of providing 104 the layer stack comprising the carrier layer andthe sacrificial layer.

FIG. 3 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of providingthe carrier layer 122 on the carrier substrate 120. The carrier layer122 can be deposited onto the carrier substrate, for example. Thecarrier layer 122 can comprise silicon nitride, for example.

FIG. 4 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of providinga structured sacrificial layer 124 on the carrier layer 122. Thesacrificial layer 124 can for example be deposited onto the carrierlayer 122 and subsequently be structured, e.g. by means of aphotolithographic method and subsequent etching, in order to obtain theareas 126 of the sacrificial layer 124 in which the carrier layer 122 isexposed. By virtue of the fact that the carrier layer 122 is exposedonly in the areas 126, for example less than 40% (or 30%, or 20%, or15%, or 10%, or 5%) of the carrier layer 122 can be exposed, i.e. not becovered by the sacrificial layer 124.

As can be discerned by way of example in FIG. 4, the areas 126 of thesacrificial layer 124 in which the carrier layer 122 is exposed can beholes or trenches, for example.

By way of example, the sacrificial layer 124 can be a silicon oxidelayer, an aluminum layer, a titanium layer, or a copper layer.

FIG. 5 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 106 ofproviding a thin-film layer 128 on the structured sacrificial layer 124and, in the areas 126 of the sacrificial layer 124 in which the carrierlayer 122 is exposed, on the carrier layer 122. The thin-film layer 128can be deposited for example onto the structured sacrificial layer 124and the exposed areas of the carrier layer 122. The thin-film layer 128can have a thickness of less than 100 μm or 70 μm, or 50 μm, or 30 μm,or 20 μm, or 10 μm.

As can be discerned in FIG. 5, the thin-film layer 128 can optionally bestructured in order to obtain a structured thin-film layer 128. Thethin-film layer 128 can be structured for example by means of aphotolithographic method and subsequent etching.

By way of example, the thin-film layer 128 can be a membrane or afilter, for example of a microsystem (MEMS=microelectromechanicalsystem). The microsystem can be produced for example on the thin-filmlayer 128 (see FIG. 16), such that the thin-film layer 128 is part ofthe microsystem.

By way of example, the thin-film layer can be a polyimide layer or acombination of polyimide layer and SU-8 layer.

FIG. 6 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 108 of at leastpartly removing the sacrificial layer 124 proceeding from the thin-filmlayer 128 (=in the substrate depth direction) in order to eliminate acontact between the thin-film layer 128 and the sacrificial layer 124 atleast in areas, such that the thin-film layer 128 is carried principallyonly by the carrier layer 122. While the thin-film layer is still incontact with the carrier layer 122, the contact between the thin-filmlayer 128 and the sacrificial layer 124 has thus been eliminated for themost part by partly removing the sacrificial layer 124 proceeding fromthe thin-film layer 128.

As can be discerned in FIG. 6, the thin-film layer 128 is thus carriedonly (i.e. primarily or principally) by the carrier layer 122.

By way of example, the sacrificial layer 124 can be eliminated at leastin areas by means of an HF etch (HF=hydrofluoric acid) proceeding fromthe thin-film layer 128.

FIG. 7 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after the step ofproviding an at least single-sided-adhesive transfer carrier layer 130on the thin-film layer 128, such that the thin-film layer 128 adheres tothe transfer carrier layer 130. By way of example, the transfer carrierlayer 130 can comprise adhesive or an adhesive layer at a side facingthe thin-film layer 128. By way of example, the transfer carrier layer130 can be an adhesive tape.

FIG. 8 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 110 ofdetaching the thin-film layer 128 from the carrier layer 122. As can bediscerned in FIG. 8, the transfer carrier layer 130 can be detached inorder to detach the thin-film layer 128 adhering to the transfer carrierlayer 130 from the carrier layer 122.

FIGS. 2 to 8 show a first exemplary embodiment of a method for producinga polyimide device membrane on a carrier wafer with zero force releaseof the membrane from the carrier wafer. In this case, the polyimidedevice is processed on a silicon wafer with an oxide layer. Holes areprocessed into the oxide layer. The polyimide that flows into the holesserves as a holding area after the release process. The bottom of saidholes is covered with silicon nitride. In order to release the veryfragile device, it is possible to etch the oxide in HF. Owing to thestress/tension in the polyimide material, the HF etches very rapidlyalong the polyimide-silicon oxide surface and releases the device fromthe carrier alongside the holding pins situated on the silicon nitridesurface. After this process, the devices are fixed to the carrier waferonly by way of the holding surfaces. A frame with an adhesive tape canthen be attached to the wafer in such a way that the devices adhere tothe adhesive tape. By lifting the frame, the holding surfaces are tornaway and all the devices are released from the wafer.

In the first exemplary embodiment, it is possible to provide theextensions or holding structures at the components in the edge regionthereof, i.e. outside the sensitive structures of the component.

In the first exemplary embodiment, an etch can be carried out along theinterface between component and sacrificial material; the sacrificialmaterial is for example only partly removed (partial etching away) inorder to release the interface between component and sacrificialmaterial, such that the component can then be removed from the carrierwafer. In this case, it is possible to achieve targeted “breaking” ofthe extensions at a substantially predetermined position.

With reference to FIGS. 9 to 19, a description is given below of asecond exemplary embodiment of the method, which differs from the firstexemplary embodiment in particular in the production of the layer stackcomprising the carrier layer and the sacrificial layer.

FIG. 9 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 102 ofproviding the carrier substrate 120. The carrier substrate 120 can befor example a semiconductor substrate or semiconductor wafer, such ase.g. a silicon substrate or silicon wafer.

With reference to FIGS. 10 to 14, a more detailed description is givenbelow of providing 104 the layer stack comprising the carrier layer, afirst sacrificial layer and a second sacrificial layer.

FIG. 10 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of providinga first sacrificial layer 123 on the carrier substrate 120. The firstsacrificial layer 123 can be deposited onto the carrier substrate, forexample. The first sacrificial layer 123 can be for example a siliconoxide layer, an aluminum layer, a titanium layer or a copper layer.

FIG. 11 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step ofstructuring the first sacrificial layer 123. The first sacrificial layer123 can be structured for example by means of a photolithographic methodand subsequent etching.

As can be discerned in FIG. 11, the first sacrificial layer 123 cancomprise elevations 127. By way of example, the elevations 127 can havea surface area (parallel to a surface 125 of the carrier substrate 120)of less than 40% (or 30%, or 20%, or 15%, or 10%, or 5%) of a totalsurface area of the (previously) deposited first sacrificial layer 123.

FIG. 12 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of providingthe carrier layer 122 on the first sacrificial layer 123. The carrierlayer 122 can be deposited for example onto the first sacrificial layer(and onto the carrier substrate 120). The carrier layer 122 can comprisenitride or silicon nitride, for example.

As can be discerned in FIG. 12, the carrier layer 122 can be applied onthe elevations 127 of the first sacrificial layer 123 and on the carriersubstrate 120.

FIG. 13 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of providingthe second sacrificial layer 124 on the carrier layer 122. The secondsacrificial layer 124 can be deposited onto the carrier layer 122, forexample. By way of example, the second sacrificial layer 124 can be asilicon oxide layer, an aluminum layer, a titanium layer or a copperlayer.

FIG. 14 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of at leastpartly removing the second sacrificial layer 124 as far as the carrierlayer 122 on the elevations 127 of the first sacrificial layer 123 inorder to obtain the areas 126 in which the carrier layer 122 is exposed.The second sacrificial layer 124 can be removed for example as far asthe carrier layer 122 on the elevations 127 of the first sacrificiallayer 123 by means of a planarization method, such as e.g. chemicalmechanical polishing, in order to obtain the areas 126 in which thecarrier layer 122 is exposed. By virtue of the fact that the carrierlayer 122 is exposed only in the areas 126, for example less than 40%(or 30%, or 20%, or 15%, or 10%, or 5%) of the carrier layer 122 can beexposed, i.e. not be covered by the sacrificial layer 124.

FIG. 15 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 106 ofproviding a thin-film layer 128 on the structured sacrificial layer 124and, in the areas 126 of the sacrificial layer 124 in which the carrierlayer 122 is exposed, on the carrier layer 122. The thin-film layer 128can be deposited for example onto the structured sacrificial layer 124and the exposed areas of the carrier layer 122. The thin-film layer 128can have a thickness of less than 100 μm or 70 μm, or 50 μm, or 30 μm,or 20 μm, or 10 μm, or 5 μm.

As can be discerned in FIG. 15, the thin-film layer 128 can optionallybe structured in order to obtain a structured thin-film layer 128. Thethin-film layer 128 can be structured for example by means of aphotolithographic method and subsequent etching.

By way of example, the thin-film layer 128 can be a membrane or afilter, for example of a microsystem (MEMS=microelectromechanicalsystem). The microsystem can be produced on the thin-film layer 128, forexample, such that the thin-film layer 128 is part of the microsystem,as can be discerned in FIG. 16.

FIG. 16 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after an optional step ofproducing microsystems 140 on the structured thin-film layer 128, suchthat the thin-film layer is part of the microsystems 140.

By way of example, a Si wafer (e.g. 100 μm thick) can be applied on apolymer material on the top side (wafer bonding), whereupon the siliconmaterial is processed and then debonded.

By way of example, the processed silicon MEMS elements 140 can bearranged above the thin-film layer 128 (bond layer, e.g. SU8 polymer),as can be discerned in FIG. 16. The MEMS components 140, with theassociated bond layer area, can then be debonded from the carrier waferand incorporated in the application.

FIG. 17 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 108 of at leastpartly removing the second sacrificial layer 124 proceeding from thethin-film layer 128 (=in the substrate depth direction) in order toeliminate a contact between the thin-film layer 128 and the secondsacrificial layer 124 at least in areas, such that the thin-film layer128 is carried principally only by the carrier layer 122. While thethin-film layer is still in contact with the carrier layer 122, thecontact between the thin-film layer 128 and the second sacrificial layer124 has thus been eliminated for the most part by partly removing thesacrificial layer 124 proceeding from the thin-film layer 128.

As can be discerned in FIG. 17, the thin-film layer 128 is thus carriedonly (i.e. primarily or principally) by the carrier layer 122.

By way of example, the second sacrificial layer 124 can be eliminated atleast in areas by means of an HF etch (HF=hydrofluoric acid) proceedingfrom the thin-film layer 128.

FIG. 18 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after the step ofproviding an at least single-sided-adhesive transfer carrier layer 130on the thin-film layer 128, such that the thin-film layer 128 adheres tothe transfer carrier layer 130. By way of example, the transfer carrierlayer 130 can comprise adhesive or an adhesive layer at a side facingthe thin-film layer 128. By way of example, the transfer carrier layer130 can be an adhesive tape.

If microsystems 140 were produced on the thin-film layer 128 (see FIG.16), the transfer carrier layer 130 can, of course, be provided on themicrosystems 140, such that the transfer carrier layer 130 adheres tothe microsystems 140.

FIG. 19 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step no of detachingthe thin-film layer 128 from the carrier layer 122. As can be discernedin FIG. 19, the transfer carrier layer 130 can be detached in order todetach the thin-film layer 128 adhering to the transfer carrier layer130 from the carrier layer 122.

If microsystems 140 were produced on the thin-film layer 128 (see FIG.16), the microsystems 140 can, of course, be detached together with thethin-film layer, for example by means of the transfer carrier layer 130.

In the second exemplary embodiment, it is possible to arrange theconnection structures between the components, e.g. mechanical screenelements or filter structures or else MEMS elements, at positions in theframe area, i.e. outside the active or sensitive areas. The aim of theprocedure is to subject the sensitive structures, e.g. filter elements,MEMS structures, to the lowest possible mechanical loads both whenproducing the components and when debonding them from the carrier waferor when applying them to the final application.

In the second exemplary embodiment, it is possible to provide theconnection extensions on the carrier wafer (e.g. silicon substrate) forexemplary embodiments with the components.

In exemplary embodiments, a sacrificial layer can be deposited on acarrier wafer. On said sacrificial layer it is possible to define areaswhere an adhesion force remains high and other areas where the adhesionforce can be reduced to zero by a chemical treatment, e.g. byundercutting by HF. After the chemical treatment, the device can adhereto the carrier wafer only by means of the high force areas. An adhesivetape can be attached to the devices. The devices can be torn away fromthe carrier wafer. The high force areas can be torn away for example atthe interface.

In exemplary embodiments, substantially no production steps (processes)are carried out at open structures (e.g. filter structures, MEMSelements, etc.). There is substantially no need for any mechanical forceduring debonding and no need for any chemical (e.g. water) duringdebonding of the sensitive structures from the carrier wafer that mighthave a negative effect on the sensitive elements. Only a wet-chemicalprocess takes place during exposing (releasing or removing a sacrificialmaterial layer), but mechanical forces acting on the sensitive areas ofthe components do not occur.

In exemplary embodiments, the following material combinations can beused for the high force areas/low force areas, wherein the releaseinterface and the release chemical can be varied:

(1) Sacrificial layer: silicon oxide

High force area: silicon nitride

Low force area: silicon oxide

Release interface: polyimide-silicon oxide

Release chemical: HF

(2) Sacrificial layer: Al

High force area: silicon nitride

Low force area: Al

Release interface: polyimide-Al

Release chemical: HF

(3) Sacrificial layer: titanium

High force area: silicon nitride

Low force area: titanium

Release interface: polyimide-titanium

Release chemical: HF

(4) Sacrificial layer: copper

High force area: silicon nitride

Low force area: copper

Release interface: silicon nitride-copper

Release chemical: EKC265, further copper etching

A further method for producing the thin-film layer is described below.

FIG. 20 shows a flow diagram of a method 200 for producing a thin-filmlayer. The method 200 comprises a step of providing 202 a carriersubstrate. Furthermore, the method 200 comprises a step 204 of providinga sacrificial layer on the carrier substrate. Furthermore, the method200 comprises a step 206 of providing the thin-film layer on thesacrificial layer. Furthermore, the method 200 comprises a step 208 ofstructuring the thin-film layer in order to obtain in a lateral plane ofthe thin-film layer an inner area of the thin-film layer which is atleast partly surrounded by an outer area of the thin-film layer, whereinduring the process of structuring the thin-film layer, at least oneopening arises in the thin-film layer which at least partially frees theinner area of the thin-film layer in the lateral plane, wherein duringthe process of structuring the thin-film layer, at least two webs remainwhich extend in a lateral plane of the thin-film layer from the outerarea of the thin-film layer into the opening in the direction of theinner area of the thin-film layer. Furthermore, the method 200 comprisesa step 210 of at least partly removing the sacrificial layer proceedingfrom the thin-film layer in order to eliminate a contact between theinner area of the thin-film layer and the sacrificial layer.Furthermore, the method 200 comprises a step 212 of detaching the innerarea of the thin-film layer from the outer area of the thin-film layer.

Exemplary embodiments of the method 200 are described in detail belowwith reference to FIGS. 21 to 26, which show schematic sectional viewsof intermediate products of producing a thin-film layer after thevarious method steps.

FIG. 21 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 202 ofproviding the carrier substrate 120. The carrier substrate 120 can befor example a semiconductor substrate or semiconductor wafer, such ase.g. a silicon substrate or silicon wafer.

FIG. 22 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 204 ofproviding the sacrificial layer 124 on the carrier substrate 120. Thesacrificial layer 124 can be a silicon oxide layer, for example.

FIG. 23 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 206 ofproviding the thin-film layer 128 on the sacrificial layer 124 and afterstep 208 of structuring the thin-film layer 128.

As is indicated in FIG. 23, structuring the thin-film layer 128 results,in a lateral plane of the thin-film layer 128, in an inner area 160 ofthe thin-film layer 128 which is at least partly surrounded by an outerarea 162 of the thin-film layer 128, wherein during the process ofstructuring the thin-film layer, at least one opening arises in thethin-film layer which at least partially frees the inner area 160 of thethin-film layer in the lateral plane, wherein during the process ofstructuring the thin-film layer, at least two webs 164 remain whichextend in a lateral plane of the thin-film layer 128 from the outer area162 of the thin-film layer 128 into the opening in the direction of theinner area 160 of the thin-film layer 128.

The thin-film layer 128 can be deposited onto the sacrificial layer 124,for example. The thin-film layer 128 can have a thickness of less than100 μm (or 70 μm, or 50 μm, or 30 μm, or 20 μm, or 10 μm, or 5 μm).

The thin-film layer 128 can be structured for example by means of aphotolithographic method and subsequent etching.

By way of example, the thin-film layer 128 can be a membrane or afilter, for example of a microsystem (MEMS=microelectromechanicalsystem). The microsystem can be produced on the thin-film layer 128, forexample, such that the thin-film layer 128 is part of the microsystem.

By way of example, the thin-film layer can be a polyimide layer or acombination of polyimide layer and SU 8 layer.

FIG. 24 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 210 of at leastpartly removing the sacrificial layer 124 proceeding from the thin-filmlayer 128 (=in the substrate depth direction) in order to eliminate acontact between the inner area 160 of the thin-film layer 128 and thesacrificial layer 124.

As can be discerned in FIG. 13, the inner area 160 of the thin-filmlayer 128, after at least partly removing the sacrificial layer belowthe inner area 160 of the thin-film layer 128, is carried only by the atleast two webs 164 of the outer area 162 of the thin-film layer 128.

By way of example, the sacrificial layer 124 can be at least partlyremoved proceeding from the thin-film layer 128 by means of an HF etch(HF=hydrofluoric acid).

Step 212 of detaching the inner area 160 of the thin-film layer 128 fromthe outer area 162 of the thin-film layer 128 is explained in greaterdetail below with reference to FIGS. 25 and 26.

FIG. 25 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after the step ofproviding an at least single-sided-adhesive transfer carrier layer 130on the thin-film layer 128, such that the inner area 160 of thethin-film layer 128 adheres to the transfer carrier layer 130. By way ofexample, the transfer carrier layer 130 can comprise adhesive or anadhesive layer at a side facing the thin-film layer 128. By way ofexample, the transfer carrier layer 130 can be an adhesive tape.

FIG. 26 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after the step ofdetaching the transfer carrier layer 130 in order to detach the innerarea 160 of the thin-film layer 128 adhering to the transfer carrierlayer 130 from the outer area 162 of the thin-film layer 128.

During the process of detaching the inner area 160 of the thin-filmlayer 128 from the outer area 162 of the thin-film layer 128, the atleast two webs 164 of the outer area 162 of the thin-film layer 128 canbreak.

Step 208 of structuring the thin-film layer is explained in greaterdetail below with reference to FIGS. 27 to 30. Furthermore, furtheroptional steps of the method 200 are explained and differentconfigurations (designs) of the horizontal holding structure are shownin FIGS. 27 and 30.

FIG. 27a shows a schematic plan view of the thin-film layer 128 afterstep 208 of structuring the thin-film layer 128. As can be discerned inFIG. 27a , structuring the thin-film layer 128 results, in a lateralplane of the thin-film layer 128, in the inner area 160 of the thin-filmlayer 128 which is surrounded by the outer area 162 of the thin-filmlayer 128, wherein during the process of structuring the thin-film layer128, at least two openings 166 can arise in the thin-film layer 128which partially (i.e. not completely) free the inner area 160 of thethin-film layer 128 in the lateral plane, wherein during the process ofstructuring the thin-film layer 128, at least two webs 164 remainbetween the openings 166, which connect the inner area 160 of thethin-film layer 128 to the outer area 162 of the thin-film layer 128.

By way of example, during the process of structuring the thin-film layer128, the inner area 160 of the thin-film layer 128 can be only partlyseparated from the outer area 162 of the thin-film layer 128, that is tosay that although openings 166 arise between the inner area 160 of thethin-film layer 128 and the outer area 162 of the thin-film layer 128,these are still connected by (thin) webs 164, such that after removingthe sacrificial layer 124 at least below the inner area 160 of thethin-film layer 128 and at least partly below the at least two webs 164,e.g. by undercutting, the inner area 160 of the thin-film layer iscarried by the at least two webs 164 of the outer area 162 of thethin-film layer 128.

The outer area 162 of the thin-film layer 128 can form for example aframe or a frame structure 162 that surrounds the inner area 160 of thethin-film layer 128. Although in FIG. 27a the frame structure 162completely surrounds the inner area 160 of the thin-film layer 128, itis equally possible for the frame structure 162 only partly to surroundthe inner area 160 of the thin-film layer 128, for example at oppositesides of the inner area 160 of the thin-film layer 128.

The inner area 160 of the thin-film layer 128 can be for example amembrane or a filter, e.g. for a microsystem (MEMS). By way of example,the microsystem can be produced on the inner area 160 of the thin-filmlayer 128, wherein during the process of detaching the inner area 160 ofthe thin-film layer 128, the microsystem can be detached together withthe inner area 160 of the thin-film layer.

FIG. 27b shows a schematic plan view of the outer area 162 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

During the process of detaching the inner area 160 of the thin-filmlayer 128 from the outer area 162 of the thin-film layer 128, the webs164 of the outer area 162 of the thin-film layer 128 can break.

FIG. 27c shows a schematic plan view of the inner area 160 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

FIG. 28a shows a schematic plan view of the thin-film layer 128 afterstep 208 of structuring the thin-film layer 128. As can be discerned inFIG. 28a , structuring the thin-film layer 128 results, in a lateralplane of the thin-film layer 128, in the inner area 160 of the thin-filmlayer 128 which is surrounded by the outer area 162 of the thin-filmlayer 128, wherein during the process of structuring the thin-film layer128, at least one opening 166 arises in the thin-film layer 128 whichfrees the inner area 160 of the thin-film layer 128 in the lateralplane, wherein during the process of structuring the thin-film layer128, at least two webs 164 remain which extend in the lateral plane ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128 into the opening 166 in the direction of the inner area 160 of thethin-film layer 128.

As can be discerned in FIG. 28a , the inner area 160 of the thin-filmlayer 128 can be completely freed from the outer area 162 of thethin-film layer 128, that is to say that after structuring the thin-filmlayer 128, the inner area 160 of the thin-film layer 128 can becompletely separated from the outer area 162 of the thin-film layer 128,and also (initially) not be connected to the outer area 162 of thethin-film layer 128 via the at least two webs 164 extending into theopening 166 in the direction of the inner area 160 of the thin-filmlayer 128.

After structuring the thin-film layer 128, a carrier layer can beprovided (e.g. deposited) on the thin-film layer 128 and be structuredin order to obtain a carrier structure 170 extending over the inner area160 of the thin-film layer 128 and at least partly over the webs 164,such that the carrier structure 170 connects the inner area 160 of thethin-film layer 128 to the webs 164.

By way of example, after structuring the thin-film layer 128, thecarrier layer can be provided (deposited) on the thin-film layer 128 andon the sacrificial layer 124 in the region of the opening 166 of thethin-film layer 128.

The carrier layer can have a thickness of more than 30 μm (or 40 μm or50 μm). By way of example, the thickness of the carrier layer can be inthe range of 40 μm to 100 μm. The carrier layer can be a polymer layer,such as e.g. an SU-8 layer.

After structuring the carrier layer, the carrier structure can thusextend at least partly over the opening 166 between the inner area 160of the thin-film layer 128 and the outer area 162 of the thin-film layer128, e.g. between the areas of the at least two webs 164.

By way of example, as can be discerned in FIG. 28a , the carrier layercan be structured such that the resulting carrier structure (orstructured carrier layer) covers the inner area 160 of the thin-filmlayer 128 and extends as far as the at least two webs 164, such that theinner area 160 of the thin-film layer 128 is connected to the at leasttwo webs 164 via the carrier structure 170, such that after removing thesacrificial layer 124 below the inner area 160 of the thin-film layer128 and at least partly below the at least two webs 164, e.g. byundercutting, the inner area 160 of the thin-film layer 128 is carriedby the at least two webs 164 of the outer area 162 of the thin-filmlayer 128 by way of the carrier structure 170.

After step 210 of at least partly removing the sacrificial layer 124,the inner area 160 of the thin-film layer 128 can thus be carried by theat least two webs 164 of the outer area 162 of the thin-film layer 128by way of the carrier structure 170. As can be discerned in FIG. 28a ,the carrier structure 170 can extend at least partly over the at leasttwo webs 164, such that the carrier structure 170 bears on the at leasttwo webs 164 of the outer area 162 of the thin-film layer 128.

By way of example, the sacrificial layer 124 can be at least partlyremoved by etching proceeding from the thin-film layer 128 in order toeliminate the contact between the inner area 160 of the thin-film layer128 and the sacrificial layer 124. By way of example, the sacrificiallayer 124 can be undercut in the area below the inner area 160 of thethin-film layer 128, while a top side of the inner area 160 of thethin-film layer is protected by the carrier structure 170 duringetching, such that the inner area 160 of the thin-film layer 128 isundercut proceeding from the opening 166 between the inner area 160 ofthe thin-film layer 128 and the outer area 162 of the thin-film layer128. Here the carrier layer (or carrier structure 170) and/or thesacrificial layer 124 can have in each case a higher etching rate thanthe thin-film layer 128.

During step 110 of detaching the inner area 160 of the thin-film layer128, the carrier structure 170 can be detached together with the innerarea 160 of the thin-film layer 128.

The outer area 162 of the thin-film layer 128 can form for example aframe or a frame structure 162 that surrounds the inner area 160 of thethin-film layer 128. Although in FIG. 28a the frame structure 162completely surrounds the inner area 160 of the thin-film layer 128, itis equally possible for the frame structure 162 only partly to surroundthe inner area 160 of the thin-film layer 128, for example at oppositesides of the inner area 160 of the thin-film layer 128.

The inner area 160 of the thin-film layer 128 can be for example amembrane or a filter, e.g. for a microsystem (MEMS). By way of example,a microsystem can be produced on the inner area 160 of the thin-filmlayer 128 before providing the carrier layer, wherein during the processof detaching the inner area 160 of the thin-film layer 128, themicrosystem can be detached together with the carrier structure 170 andthe inner area 160 of the thin-film layer.

FIG. 28b shows a schematic plan view of the outer area 162 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

During the process of detaching the inner area 160 of the thin-filmlayer 128 from the outer area 162 of the thin-film layer 128, the webs164 of the outer area 162 of the thin-film layer 128 can break.

FIG. 28c shows a schematic plan view of the inner area 160 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

In other words, FIG. 28a shows the device before release, while FIG. 28bshows the frame 162 and FIG. 28c the device after release. As can bediscerned in FIGS. 28a to 28c , the holding structure 164 is torn awayduring the release of the device. Parts of the holding structure 164remain at the device.

FIG. 29a shows a schematic plan view of the thin-film layer 128 afterstep 208 of structuring the thin-film layer 128 and the step ofproviding the carrier structure 170. In contrast to FIG. 28a , thethin-film layer 128 can be structured such that the at least two webs164 each have a tapering area 165 in the center. The tapering areas 165of the at least two webs 164 can be predetermined breaking locations165, for example, which define the locations at which the at least twowebs 164 break during the process of detaching the inner area 160 of thethin-film layer 128.

FIG. 29b shows a schematic plan view of the outer area 162 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

During the process of detaching the inner area 160 of the thin-filmlayer 128 from the outer area 162 of the thin-film layer 128, the webs164 of the outer area 162 of the thin-film layer 128 can break at thepredetermined breaking locations 165.

FIG. 29c shows a schematic plan view of the inner area 160 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

In other words, FIG. 29a shows the device before release, while FIG. 29bshows the frame 162 and FIG. 29c the device after release. As can bediscerned in FIGS. 29a to 29c , the holding structure 164 has a doubletaper, that is to say that the holding structure 164 has a taper fromboth sides. In this case, the holding structure 164 breaks at thethinnest location.

FIG. 30a shows a schematic plan view of the thin-film layer 128 afterstep 208 of structuring the thin-film layer 128 and the step ofproviding the carrier structure 170. In contrast to FIG. 28a , thethin-film layer 128 can be structured such that the at least two webs164 each have a tapering area 165 at the ends. The tapering areas 165 ofthe at least two webs 164 can be predetermined breaking locations 165,for example, which define the locations at which the at least two webs164 break during the process of detaching the inner area 160 of thethin-film layer 128.

FIG. 30b shows a schematic plan view of the outer area 162 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

During the process of detaching the inner area 160 of the thin-filmlayer 128 from the outer area 162 of the thin-film layer 128, the webs164 of the outer area 162 of the thin-film layer 128 can break at thepredetermined breaking locations 165.

FIG. 30c shows a schematic plan view of the inner area 160 of thethin-film layer 128 after step 212 of detaching the inner area 160 ofthe thin-film layer 128 from the outer area 162 of the thin-film layer128.

In other words, FIG. 30a shows the device before release, while FIG. 30bshows the frame 162 and FIG. 30c the device after release. As can bediscerned in FIGS. 30a to 30c , the holding structure 164 has a singletaper, that is to say that the holding structure 164 has in each case ataper that becomes narrower in the direction of the device. On accountof said taper, the holding structure 164 can be debonded from the deviceduring the release of the device.

In exemplary embodiments, the following material combinations can beused for the high force areas/low force areas, wherein the releaseinterface and the release chemical can be varied:

(1) Sacrificial layer: silicon oxide

Holding structure of the kerf: polyimide or PBO

Device frame (carrier structure): SU 8

Release interface: polyimide-silicon oxide

Release chemical: HF

The material combination polyimide/SU-8 is very well suited to thismethod. The polyimide is used for holding the structure in the kerf andthe lattice of the MEMS device. During oxide etching, the polyimide isundercut only from the left and right. It can therefore withstand longetching times before the delamination of the device. In this case, SU-8can serve as a frame for handling the device. During oxide etching, thematerial can be penetrated by the etchant that attacks the SU-8/oxideinterface. The delamination of the device therefore takes place muchfaster. As a result of this material combination, it is possible tosignificantly reduce the required etching time for releasing the deviceduring oxide etching.

FIG. 31 shows a schematic plan view of the thin-film layer 128 afterstep 208 of structuring the thin-film layer 128 and the step ofproviding the carrier structure 170. As can be discerned in FIG. 31,structuring the thin-film layer 128 results, in a lateral plane of thethin-film layer 128, in the inner area 160 of the thin-film layer 128which is surrounded by the outer area 162 of the thin-film layer 128,wherein during the process of structuring the thin-film layer 128, atleast two webs 164 remain which extend in the lateral plane of thethin-film layer 128 from the outer area 162 of the thin-film layer 128in the direction of the inner area 160 of the thin-film layer 128,wherein the carrier structure extends at least partly over the at leasttwo webs 164, such that the carrier structure 170 bears on the at leasttwo webs 164 of the outer area 162 of the thin-film layer.

The methods described herein can be used for example for producingparticle filters for MEMS microphones having a filter thickness of e.g.5 μm. In contrast to other methods, the thin filter area is notsubjected to force loading during debonding from the carrier.

The methods described herein have the advantage that the clean roomrequirements during the assembly of cellular phones, for example, can bereduced since the MEMS microphone module is protected by a particlefilter.

Although a description has been given here of exemplary embodiments inwhich the thin-film layer is a polyimide layer or comprises polyimide,it should be pointed out that some other material, such as e.g. silicon,can also be used instead of a polyimide layer or polyimide.

A description is given below of further exemplary embodiments which canbe applied by themselves or in combination with the exemplaryembodiments described above.

In exemplary embodiments, the thin-film layer 128 (e.g. a particlebarrier, a membrane or a filter) can be processed on the carriersubstrate (carrier wafer) 120. After processing the thin-film layer 128or the semiconductor device (e.g. microsystem) having the thin-filmlayer 128, the thin-film layer 128 or the semiconductor device havingthe thin-film layer 128 can be released from the carrier substrate 120.In order that the thin-film layer 128, during release from the carriersubstrate 120, does not stick to the carrier substrate 120 and break, ananti-sticking structure can be used in exemplary embodiments. Theanti-sticking structure makes it possible to reduce a contact area withrespect to the thin-film layer 128, such that the thin-film layer 128,during release from the carrier substrate 120, does not stick to thecarrier substrate 120 and break.

In exemplary embodiments, before providing the sacrificial layer 124, ananti-sticking structure can be provided on the carrier substrate 120,wherein the anti-sticking structure comprises elevations (e.g. (linear)dams or dykes) extending in at least one lateral dimension along asurface of the carrier substrate 120. The anti-sticking structure can bearranged in a vertical plane below the thin-film layer 128 or the innerarea 160 of the thin-film layer 128.

In exemplary embodiments, the elevations can have a width (e.g. in alateral plane) of less than 2 μm, e.g. a width of 1 μm. Furthermore, theelevations can have a length (e.g. in a lateral plane) of more than 100μm (or 200 μm, or 300 μm, or 400 μm, or 500 μm, or 600 μm, or 700 μm, or800 μm), such as e.g. a length of approximately 850 μm.

In exemplary embodiments, the elevations can extend in one lateraldimension along a surface of the carrier substrate 120, wherein theelevations form a line in a lateral plane (of the elevations).

In exemplary embodiments, the elevations can extend in two lateraldimensions along a surface of the carrier substrate 120, wherein theelevations form circles in a lateral plane (of the elevations). In thiscase, a diameter of the circles can be greater than a diameter of theopenings of a lattice structure of the thin-film layer 128 (e.g.particle barrier, membrane or filter).

On the one hand, the thin-film layer can be detached from the carriersubstrate 120 by means of the anti-sticking structure after the releaseetch (e.g. undercutting), without the thin-film layer 128 sticking tothe carrier substrate 120 and breaking. On the other hand, the specificconfiguration of the anti-sticking structure (elevations or linesextending in at least one lateral dimension) makes it possible to ensurethat the thin-film layer does not detach easily (e.g. of its own accord)from the anti-sticking structure.

In contrast thereto, in the case of a conventional anti-stickingstructure based on pyramidal pins, the thin-film layer can be moved in alateral plane (e.g. in x- and y-directions) after the release etch (e.g.undercutting) and thus fall off easily (e.g. of its own accord) from theanti-sticking structure.

FIG. 32 shows a recording (e.g. scanning electron microscope recording)of a thin-film layer and of an anti-sticking structure 129 having anelevation extending in one lateral dimension. As can be discerned inFIG. 32, the anti-sticking structure does not have punctiform pyramids,but rather thin straight lines or linear elevations (having a width ofe.g. 1 μm, and a length of ˜850 μm). Alternatively, the anti-stickingstructure 129 can comprise circles or circular elevations, wherein adiameter of the circles is greater than a diameter of the holes oropenings of a lattice structure of the thin-film layer.

FIG. 33 shows a microscope recording of the thin-film layer before thestep of providing the carrier structure. In detail, FIG. 33 shows thethin-film layer in finished processed form on the carrier substrate. Theholes of the filter structure of 7 μm cannot be discerned on account ofthe low microscope magnification chosen. The anti-sticking structure(vertical and diagonal lines) lying below the thin-film layer can bediscerned in the central region of the filter structure.

In exemplary embodiments, the anti-sticking structure 129 can comprisestraight lines or linear elevations or concentric circles or circularelevations (e.g. having a line width of 1 μm). The anti-stickingstructure 129 can be arranged below the thin-film layer 128 (e.g.particle barrier, membrane or filter).

In exemplary embodiments, the barrier layer of the particle barrier canbe produced in various designs. The lattice causes noises if air passesthrough the lattice. Therefore, in exemplary embodiments, for thelattice structure a design having the highest hole-to-barrier ratio canbe chosen, which is a hexagonal lattice, in order to reduce or evenminimize the signal-to-noise ratio.

In exemplary embodiments, the inner area 160 of the thin-film layer 128can comprise a lattice structure having hexagonal openings.

FIG. 34 shows a schematic sectional view of the thin-film layer 128 anda schematic plan view of the thin-film layer 128, wherein the inner area160 of the thin-film layer 128 comprises a lattice structure havinghexagonal openings 131, wherein the inner area 160 of the thin-filmlayer 128 is carried by the outer area 162 of the thin-film layer.

There are a number of possibilities for shipping the thin-film layer ora semiconductor device (e.g. a device or a microsystem) having thethin-film layer 128. By way of example, the semiconductor device can beshipped on a wafer or a film frame. For shipping the thin-film layer 128or the semiconductor device having the thin-film layer 128 on a filmframe, by way of example, a single-sided-adhesive transfer carrier layer(e.g. adhesive tape) 130 can be laminated on the wafer and the transfercarrier layer 130 can be detached from the wafer, wherein in this casethe thin-film layer or the semiconductor device having the thin-filmlayer 128 sticks to the transfer carrier layer 130. Areas on the waferon which e.g. no particle barrier is present are normally completelywithout a structure or completely filled. If this is the case, debondingthe transfer carrier layer 130 from the wafer in these areas requires ahigh force since the transfer carrier layer 130 sticks to the wafer onthe entire area. In exemplary embodiments, therefore, anti-stickingstructures can be used in these areas in order to reduce the adhesionand hence the detachment force of the transfer carrier layer 130.

In exemplary embodiments, a further anti-sticking structure can beprovided on an outer area 162 of the thin-film layer 128 or on a layerarranged thereon, such that during the process of detaching the innerarea 160 of the thin-film layer 128 (or the semiconductor device havingthe inner area 160 of the thin-film layer 128) adhering to the transfercarrier layer from the outer area 162 of the thin-film layer 128, thetransfer carrier layer 130 detaches more easily from the outer area 162of the thin-film layer or from the layer arranged thereon.

In order to reduce the force required for detaching the transfer carrierlayer 130 from the wafer, in exemplary embodiments, anti-stickingstructures can be arranged in areas without a semiconductor device (e.g.mirror forms, notches, edge exclusion). The anti-sticking structures(e.g. SU-8) can have for example a size of 80×80 μm and be for exampleat a distance of 300 μm from one another.

In exemplary embodiments, the inner area 160 of the thin-film layer 128or the semiconductor device (e.g. microsystem) having the inner area 160of the thin-film layer 128 can also be detached from the outer area 162of the thin-film layer 128 by means of a pick-and-place method.

Semiconductor devices are normally delivered to the customer on filmframes (diced or cut), on so-called “tape and reel” packaging, as“waffle pack” or as wafers. The particle barrier (or membrane or filter)can be delivered to the customer on a film frame, wherein, in exemplaryembodiments, the particle barrier or the device having the particlebarrier can be transferred from the carrier wafer to the film frame bymeans of a pick-and-place method.

In order to avoid the process of transferring the particle barrier fromthe carrier wafer to the film frame, in exemplary embodiments, theparticle barrier or the device having the particle barrier can also bepicked up directly from the carrier wafer by means of a pick-and-placemethod. During the process of picking up the particle barrier or thedevice having the particle barrier, the holding structures that hold theparticle barrier in its place tear or break.

A further method for producing the thin-film layer is described below.

FIG. 35 shows a flow diagram of a method 200 for producing a thin-filmlayer. The method 200 comprises a step 202 of providing a carriersubstrate. Furthermore, the method 20, comprises a step 203 of providingan anti-sticking structure on the carrier substrate. Furthermore, themethod comprises a step 204 of providing a sacrificial layer on theanti-sticking structure and the carrier substrate. Furthermore, themethod 200 comprises a step 206 of providing the thin-film layer on thesacrificial layer. Furthermore, the method comprises a step ofstructuring 208 the thin-film layer in order to obtain in a lateralplane of the thin-film layer an inner area of the thin-film layer whichis at least partly surrounded by an outer area of the thin-film layerand is arranged in a vertical direction above the anti-stickingstructure, wherein during the process of structuring the thin-filmlayer, at least one opening arises in the thin-film layer which at leastpartially frees the inner area of the thin-film layer in the lateralplane, wherein during the process of structuring the thin-film layer, atleast two webs remain which extend in a lateral plane of the thin-filmlayer from the outer area of the thin-film layer into the opening in thedirection of the inner area of the thin-film layer. Furthermore, themethod 200 comprises a step 210 of at least partly removing thesacrificial layer proceeding from the thin-film layer in order toeliminate a contact between the inner area of the thin-film layer andthe sacrificial layer, wherein during the process of at least partlyremoving the sacrificial layer, the anti-sticking structure is at leastpartly exposed.

Exemplary embodiments of the method 200 are described in detail belowwith reference to FIGS. 36 to 45, which show schematic sectional viewsof intermediate products of the production of a thin-film layer afterthe various method steps.

FIG. 36 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after steps 202, 203 and204 of providing the carrier substrate 120, providing the anti-stickingstructure 129 on the carrier substrate 120 and providing the sacrificiallayer 124 on the anti-sticking structure 129 and the carrier substrate120.

The carrier substrate 120 can be for example a semiconductor substrateor semiconductor wafer, such as e.g. a silicon substrate or siliconwafer.

The anti-sticking structure 129 can comprise elevations (e.g. dams ordykes) extending in at least one lateral dimension along a surface ofthe carrier substrate 120.

The elevations can have a width (e.g. in a lateral plane) of less than 2μm, e.g. a width of 1 μm. Furthermore, the elevations can have a length(e.g. in a lateral plane) of more than 100 μm (or 200 μm, or 300 μm, or400 μm, or 500 μm, or 600 μm, or 700 μm, or 800 μm), such as e.g. alength of approximately 850 μm.

As is indicated in FIG. 36, the elevations can extend in one lateraldimension along a surface of the carrier substrate 120, wherein theelevations form a line in a lateral plane (of the elevations).Alternatively, the elevations can extend in two lateral dimensions alongthe surface of the carrier substrate 120, wherein the elevations formcircles in a lateral plane (of the elevations). In this case, a diameterof the circles can be greater than a diameter of the openings of alattice structure of the thin-film layer 128 (e.g. particle barrier,membrane or filter).

By way of example, the anti-sticking structure 129 can compriseanti-sticking lines. The anti-sticking structure thus does not comprisepunctiform pyramids, but rather long thin lines (e.g. having a width of1 μm, for example, and/or a length of 850 μm, for example). In thiscase, the anti-sticking structure can comprise straight lines orconcentric circles (e.g. having a line width of 1 μm) below the particlebarrier.

The sacrificial layer 124 can be a silicon oxide layer, for example.

FIG. 37 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 206 ofproviding the thin-film layer 128 on the sacrificial layer 124 and afterstep 208 of structuring the thin-film layer 128.

As is indicated in FIG. 37, structuring the thin-film layer 128 results,in a lateral plane of the thin-film layer 128, in an inner area 160 ofthe thin-film layer 128 which is at least partly surrounded by an outerarea 162 of the thin-film layer 128, wherein during the process ofstructuring the thin-film layer, at least one opening arises in thethin-film layer which at least partially frees the inner area 160 of thethin-film layer in the lateral plane, wherein during the process ofstructuring the thin-film layer, at least two webs 164 remain whichextend in a lateral plane of the thin-film layer 128 from the outer area162 of the thin-film layer 128 into the opening in the direction of theinner area 160 of the thin-film layer 128.

The inner area 160 of the thin-film layer 128 can be arranged adjacentto the anti-sticking structure 129. In other words, the inner area 160of the thin-film layer can be arranged in a vertical dimension above theanti-sticking structure 129.

The thin-film layer 128 can be deposited onto the sacrificial layer 124,for example. The thin-film layer 128 can have a thickness of less than100 μm (or 70 μm, or 50 μm, or 30 μm, or 20 μm, or 10 μm, or 5 μm).

The thin-film layer 128 can be structured for example by means of aphotolithographic method and subsequent etching.

By way of example, the thin-film layer 128 can be a membrane or afilter, for example of a microsystem (MEMS=microelectromechanicalsystem). The microsystem can be produced on the thin-film layer 128, forexample, such that the thin-film layer 128 is part of the microsystem.

By way of example, the thin-film layer can be a polyimide layer or acombination of polyimide layer and SU-8 layer.

By way of example, the inner area 160 of the thin-film layer 128 cancomprise a lattice structure having hexagonal openings, wherein thelattice structure forms a particle barrier, a filter or a membrane.

By way of example, a hexagonal lattice can be used as particle barrier.The hole diameter can be between 5 μm and 100 μm. The bridge width canbe between 1 μm and 20 μm.

FIG. 38 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 210 of at leastpartly removing the sacrificial layer 124 proceeding from the thin-filmlayer 128 (=in the substrate depth direction) in order to eliminate acontact between the inner area 160 of the thin-film layer 128 and thesacrificial layer 124.

As can be discerned in FIG. 38, after at least partly removing thesacrificial layer below the inner area 160 of the thin-film layer 128,the inner area 160 of the thin-film layer 128 is carried only by the atleast two webs 164 of the outer area 162 of the thin-film layer 128.

By way of example, the sacrificial layer 124 can be at least partlyremoved proceeding from the thin-film layer 128 by means of an HF etch(HF=hydrofluoric acid).

The step 212 of detaching the inner area 160 of the thin-film layer 128from the outer area 162 of the thin-film layer 128 is explained ingreater detail below with reference to FIGS. 39 and 40.

FIG. 39 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after the step ofproviding an at least single-sided-adhesive transfer carrier layer 130on the thin-film layer 128, such that the inner area 160 of thethin-film layer 128 adheres to the transfer carrier layer 130. By way ofexample, the transfer carrier layer 130 can comprise adhesive or anadhesive layer at a side facing the thin-film layer 128. By way ofexample, the transfer carrier layer 130 can be an adhesive tape.

FIG. 40 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after the step ofdetaching the transfer carrier layer 130 in order to detach the innerarea 160 of the thin-film layer 128 adhering to the transfer carrierlayer 130 from the outer area 162 of the thin-film layer 128.

During the process of detaching the inner area 160 of the thin-filmlayer 128 from the outer area 162 of the thin-film layer 128, the atleast two webs 164 of the outer area 162 of the thin-film layer 128 canbreak.

Optionally, before providing the transfer carrier layer 130, a furtheranti-sticking structure can be provided on the outer area 162 of thethin-film layer 128 or on a layer arranged thereon. By means of thefurther anti-sticking structure, during the process of detaching theinner area 160 of the thin-film layer 128 (or the semiconductor devicehaving the inner area 160 of the thin-film layer 128) adhering to thetransfer carrier layer from the outer area 162 of the thin-film layer128, the transfer carrier layer 130 can detach more easily from theouter area 162 of the thin-film layer or from the layer arrangedthereon.

The further anti-sticking structure can comprise anti-sticking pins, forexample. The anti-sticking pins can have various shapes, such as e.g. acircular shape having a radius of 10 μm to 100 μm, or a rectangularshape having the dimensions 10×10 μm to 500×500 μm. The distance betweenthe anti-sticking pins can be between 20 μm and 2000 μm.

A further exemplary embodiment of the method 200 shown in FIG. 35 isdescribed below.

FIG. 41 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after steps 202, 203 and204 of providing the carrier substrate 120, providing the anti-stickingstructure 129 on the carrier substrate 120 and providing the sacrificiallayer 124 on the anti-sticking structure 129 and the carrier substrate120.

The carrier substrate 120 can be for example a semiconductor substrateor semiconductor wafer, such as e.g. a silicon substrate or siliconwafer.

The anti-sticking structure 129 can comprise elevations (e.g. dams ordykes) extending in at least one lateral dimension along a surface ofthe carrier substrate 120.

The elevations can have a width (e.g. in a lateral plane) of less than 2μm, e.g. a width of 1 μm. Furthermore, the elevations can have a length(e.g. in a lateral plane) of more than 100 μm (or 200 μm, or 300 μm, or400 μm, or 500 μm, or 600 μm, or 700 μm, or 800 μm), such as e.g. alength of approximately 850 μm.

As is indicated in FIG. 41, the elevations can extend in one lateraldimension along a surface of the carrier substrate 120, wherein theelevations form a line in a lateral plane (of the elevations).Alternatively, the elevations can extend in two lateral dimensions alongthe surface of the carrier substrate 120, wherein the elevations formcircles in a lateral plane (of the elevations). In this case, a diameterof the circles can be greater than a diameter of the openings of alattice structure of the thin-film layer 128 (e.g. particle barrier,membrane or filter).

By way of example, the anti-sticking structure 129 can compriseanti-sticking lines. The anti-sticking structure thus does not comprisepunctiform pyramids, but rather long thin lines (e.g. having a width of1 μm, for example, and/or a length of 850 μm, for example). In thiscase, the anti-sticking structure can comprise straight lines orconcentric circles (e.g. having a line width of 1 μm) below the particlebarrier.

The sacrificial layer 124 can be a silicon oxide layer, for example.

FIG. 42 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 206 ofproviding the thin-film layer 128 on the sacrificial layer 124 and afterstep 208 of structuring the thin-film layer 128.

As is indicated in FIG. 42, structuring the thin-film layer 128 results,in a lateral plane of the thin-film layer 128, in an inner area 160 ofthe thin-film layer 128 which is at least partly surrounded by an outerarea 162 of the thin-film layer 128, wherein during the process ofstructuring the thin-film layer, at least one opening arises in thethin-film layer which at least partially frees the inner area 160 of thethin-film layer in the lateral plane, wherein during the process ofstructuring the thin-film layer, at least two webs 164 remain whichextend in a lateral plane of the thin-film layer 128 from the outer area162 of the thin-film layer 128 into the opening in the direction of theinner area 160 of the thin-film layer 128.

The inner area 160 of the thin-film layer 128 can be arranged adjacentto the anti-sticking structure 129. In other words, the inner area 160of the thin-film layer can be arranged in a vertical dimension above theanti-sticking structure 129.

The thin-film layer 128 can be deposited onto the sacrificial layer 124,for example. The thin-film layer 128 can have a thickness of less than100 μm (or 70 μm, or 50 μm, or 30 μm, or 20 μm, or 10 μm, or 5 μm).

The thin-film layer 128 can be structured for example by means of aphotolithographic method and subsequent etching.

By way of example, the thin-film layer 128 can be a membrane or afilter, for example of a microsystem (MEMS=microelectromechanicalsystem). The microsystem can be produced on the thin-film layer 128, forexample, such that the thin-film layer 128 is part of the microsystem.

By way of example, the thin-film layer can be a polyimide layer or acombination of polyimide layer and SU-8 layer.

By way of example, the inner area 160 of the thin-film layer 128 cancomprise a lattice structure having hexagonal openings, wherein thelattice structure forms a particle barrier, a filter or a membrane.

By way of example, a hexagonal lattice can be used as particle barrier.The hole diameter can be between 5 μm and 100 μm. The bridge width canbe between 1 μm and 20 μm.

FIG. 43 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after step 210 of at leastpartly removing the sacrificial layer 124 proceeding from the thin-filmlayer 128 (=in the substrate depth direction) in order to eliminate acontact between the inner area 160 of the thin-film layer 128 and thesacrificial layer 124.

As can be discerned in FIG. 43, after at least partly removing thesacrificial layer below the inner area 160 of the thin-film layer 128,the inner area 160 of the thin-film layer 128 is carried only by the atleast two webs 164 of the outer area 162 of the thin-film layer 128.

By way of example, the sacrificial layer 124 can be at least partlyremoved proceeding from the thin-film layer 128 by means of an HF etch(HF=hydrofluoric acid).

The step 212 of detaching the inner area 160 of the thin-film layer 128from the outer area 162 of the thin-film layer 128 is explained ingreater detail below with reference to FIGS. 44 and 45.

FIG. 44 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of providinga wafer 134 and mounting the carrier substrate 120 on the wafer 134before detaching the inner area 160 of the thin-film layer 128 from theouter area 162 of the thin-film layer.

FIG. 45 shows a schematic sectional view of an intermediate product 118of the method for producing a thin-film layer after a step of detachingthe inner area 160 of the thin-film layer 128 from the outer area 162 ofthe thin-film layer 128 by means of a pick-and-place method.

The pick-and-place can be implemented as pick-and-place or flip-chip.

FIG. 46 shows a schematic plan view of the thin-film layer after thestep of structuring the thin-film layer and the step of providing thecarrier structure. In detail, FIG. 46, like FIG. 31, shows a filterstructure, with the difference that the filter structure runs out in theSU-8 frame as lattice. In FIG. 31, the filter structure is closed in theSU-8 frame.

As can be discerned in FIG. 46, by virtue of the anti-sticking lines onthe carrier substrate, the particle barrier (or membrane or filter) canbe detached from the carrier substrate without the particle barrierbeing damaged.

In exemplary embodiments, the carrier substrate can compriseanti-sticking lines. The anti-sticking lines can be used asanti-sticking structures.

In exemplary embodiments, a hexagonal lattice can be used as particlebarrier. The barrier layer of the particle barrier can have a hexagonaldesign.

In exemplary embodiments, anti-sticking pins can be used in areaswithout semiconductor devices. The adhesion of the transfer carrierlayer (e.g. adhesive tape) on the carrier substrate during the transferprocess can be reduced by the positioning of anti-sticking pins in areaswithout semiconductor devices.

In exemplary embodiments, a pick-and-place method can be used.Semiconductor devices can be debonded from the carrier substrate bymeans of a pick-and-place method.

Although specific embodiments have been illustrated and described here,it is obvious to the person of average skill in the art that amultiplicity of alternative and/or equivalent implementations canreplace the specific embodiments shown and described, without departingfrom the scope of the present invention. This application is intended tocover all adaptations or variations of the specific embodimentsdiscussed herein. Therefore, the intention is for this invention to berestricted only by the claims and the equivalents thereof.

What is claimed is:
 1. A method for producing a thin-film layer, whereinthe method comprises: providing a carrier substrate; providing a layerstack on the carrier substrate, wherein the layer stack comprises acarrier layer and a sacrificial layer, wherein the sacrificial layercomprises areas in which the carrier layer is exposed; providing thethin-film layer on the layer stack, such that the thin-film layer bearson the sacrificial layer and, in the areas of the sacrificial layer inwhich the carrier layer is exposed, against the carrier layer; at leastpartly removing the sacrificial layer proceeding from the thin-filmlayer in order to eliminate a contact between the thin-film layer andthe sacrificial layer at least in areas; and detaching the thin-filmlayer from the carrier layer.
 2. The method as claimed in claim 1,wherein the thin-film layer has a thickness of less than 100 μm.
 3. Themethod as claimed in claim 1, wherein the thin-film layer is a filter ora membrane.
 4. The method as claimed claim 1, wherein the thin-filmlayer is a polyimide layer or a combination of polyimide layer and SU 8layer.
 5. The method as claimed in claim 1, wherein detaching thethin-film layer comprises the following steps: providing an at leastsingle-sided-adhesive transfer carrier layer on the thin-film layer suchthat the thin-film layer adheres to the transfer carrier layer;detaching the transfer carrier layer in order to detach the thin-filmlayer adhering to the transfer carrier layer from the carrier layer. 6.The method as claimed in claim 5, wherein the transfer carrier layercomprises an adhesive layer on a side facing the thin-film layer.
 7. Themethod as claimed in claim 5, wherein the method further comprises:structuring the thin-film layer before detaching the thin-film layer. 8.The method as claimed in claim 5, wherein the method further comprises:producing at least one microsystem on the thin-film layer; whereinduring the process of detaching the thin-film layer, the at least onemicrosystem is detached together with the thin-film layer.
 9. The methodas claimed in claim 8, wherein the thin-film layer is part of the atleast one microsystem.
 10. The method as claimed in claim 1, whereinproviding the layer stack comprises: providing the carrier layer on thecarrier substrate; providing the sacrificial layer on the carrier layer;and opening the sacrificial layer in areas as far as the carrier layerin order to obtain the areas in which the carrier layer is exposed. 11.The method as claimed in claim 10, wherein the areas in which thecarrier layer is exposed are holes.
 12. The method as claimed in claim11, wherein the holes have a diameter of 10 μm.
 13. The method asclaimed in claim 1, wherein the sacrificial layer is a secondsacrificial layer, and wherein providing the layer stack comprises thefollowing steps: providing a first sacrificial layer on the carriersubstrate, wherein the first sacrificial layer comprises elevations;providing the carrier layer on the first sacrificial layer; providingthe second sacrificial layer on the carrier layer; at least partlyremoving the second sacrificial layer as far as the carrier layer on theelevations of the first sacrificial layer in order to obtain the areasin which the carrier layer is exposed.
 14. The method as claimed inclaim 13, wherein the elevations have a diameter of 20 μm or less. 15.The method as claimed in claim 13, wherein the areas of the carrierlayer which are exposed in the areas of the sacrificial layer have asurface area of less than 40% of a total surface area of the carrierlayer.
 16. The method as claimed in claim 13, wherein the sacrificiallayer comprises silicon oxide, aluminum, titanium or copper.
 17. Themethod as claimed in claim 13, wherein the carrier layer comprisesnitride or silicon nitride.
 18. A method for producing a thin-filmlayer, wherein the method comprises: providing a carrier substrate;providing a sacrificial layer on the carrier substrate; providing thethin-film layer on the sacrificial layer; structuring the thin-filmlayer in order to obtain in a lateral plane of the thin-film layer aninner area of the thin-film layer which is at least partly surrounded byan outer area of the thin-film layer, wherein during the process ofstructuring the thin-film layer, at least one opening arises in thethin-film layer which at least partially frees the inner area of thethin-film layer in the lateral plane, wherein during the process ofstructuring the thin-film layer, at least two webs remain which extendin a lateral plane of the thin-film layer from the outer area of thethin-film layer into the opening in the direction of the inner area ofthe thin-film layer; at least partly removing the sacrificial layerproceeding from the thin-film layer in order to eliminate a contactbetween the inner area of the thin-film layer and the sacrificial layer;and detaching the inner area of the thin-film layer from the outer areaof the thin-film layer.
 19. The method as claimed in claim 18, whereinthe thin-film layer has a thickness of less than 100 μm.
 20. The methodas claimed in claim 18, wherein the inner area of the thin-film layer isa filter or a membrane.
 21. The method as claimed in claim 18, whereinthe thin-film layer is a polyimide layer or a combination of polyimidelayer and SU-8 layer.
 22. The method as claimed in claim 18, wherein theouter area of the thin-film layer forms a frame structure.
 23. Themethod as claimed in claim 18, wherein during the process of structuringthe thin-film layer, the inner area of the thin-film layer is freed inthe lateral plane of the thin-film layer; wherein the method furthercomprises providing a carrier layer on the thin-film layer; wherein themethod further comprises structuring the carrier layer in order toobtain a carrier structure extending over the inner area of thethin-film layer and at least partly over the webs, wherein the carrierstructure connects the inner area of the thin-film layer to the webs.24. The method as claimed in claim 23, wherein after at least partlyremoving the sacrificial layer, the inner area of the thin-film layer iscarried by the at least two webs by way of the carrier structure. 25.The method as claimed in claim 23, wherein during the process ofdetaching the inner area of the thin-film layer, the carrier structureis detached together with the inner area of the thin-film layer.
 26. Themethod as claimed in claim 23, wherein the carrier layer, after theprocess of structuring the thin-film layer, is provided on the thin-filmlayer and on the sacrificial layer in the region of the opening of thethin-film layer.
 27. The method as claimed in claim 23, wherein thecarrier layer has a thickness of more than 30 μm.
 28. The method asclaimed in claim 23, wherein the carrier layer is an SU-8 layer.
 29. Themethod as claimed in claim 18, wherein during the process of structuringthe thin-film layer, at least two openings arise in the thin-film layerwhich partially free the inner area of the thin-film layer in thelateral plane, wherein the at least two webs remain between the openingsand connect the inner area of the thin-film layer to the outer area ofthe thin-film layer.
 30. The method as claimed in claim 29, whereinafter at least partly removing the sacrificial layer, the inner area ofthe thin-film layer is carried by the at least two webs.
 31. The methodas claimed in claim 18, wherein the at least two webs in each casecomprise a tapering area.
 32. The method as claimed in claim 18, whereinduring the process of detaching the inner area of the thin-film layerfrom the outer area of the thin-film layer, the at least two webs break.33. The method as claimed in claim 18, wherein detaching the thin-filmlayer comprises the following steps: providing an at leastsingle-sided-adhesive transfer carrier layer on the inner area of thethin-film layer; detaching the transfer carrier layer in order to detachthe inner area of the thin-film layer adhering to the transfer carrierlayer from the outer area of the thin-film layer.
 34. The method asclaimed in claim 18, wherein the transfer carrier layer comprises anadhesive layer on a side facing the thin-film layer.
 35. The method asclaimed in claim 18, wherein the method further comprises: producing atleast one microsystem on the inner area of the thin-film layer; whereinduring the process of detaching the inner area of the thin-film layer,the at least one microsystem is detached together with the inner area ofthe thin-film layer.
 36. The method as claimed in claim 35, wherein theinner area of the thin-film layer is part of the at least onemicrosystem.
 37. The method as claimed in claim 18, wherein thesacrificial layer comprises silicon oxide.
 38. The method as claimed inclaim 18, wherein the method further comprises: providing ananti-sticking structure on the carrier substrate, wherein thesacrificial layer is provided on the carrier substrate and theanti-sticking structure, wherein the inner area of the thin-film layerthat results during the process of structuring the thin-film layer isarranged adjacent to the anti-sticking structure, wherein during theprocess of at least partly removing the sacrificial layer, theanti-sticking structure is at least partly exposed, wherein during theprocess of detaching the inner area of the thin-film layer, the innerarea of the thin-film layer is lifted off from the anti-stickingstructure.
 39. The method as claimed in claim 38, wherein theanti-sticking structure comprises elevations extending in at least onelateral dimension along a surface of the carrier substrate.
 40. Themethod as claimed in claim 39, wherein the elevations have a width ofless than 2 μm.
 41. The method as claimed in claim 39, wherein theelevations extend in one lateral dimension, wherein the elevations, in alateral plane of same, form lines, or wherein the elevations extend intwo lateral dimensions, wherein the elevations, in a lateral plane ofsame, form circles.
 42. The method as claimed in claim 18, wherein theinner area of the thin-film layer comprises a lattice structure havinghexagonal openings, wherein the lattice structure forms a particlebarrier, a filter or a membrane.
 43. The method as claimed in claim 18,wherein the method further comprises: providing a further anti-stickingstructure on an outer area of the thin-film layer or on a layer arrangedthereon, wherein detaching the thin-film layer comprises the followingsteps: providing an at least single-sided-adhesive transfer carrierlayer on the inner area of the thin-film layer and the furtheranti-sticking structure; detaching the transfer carrier layer in orderto detach the inner area of the thin-film layer adhering to the transfercarrier layer from the outer area of the thin-film layer.
 44. The methodas claimed in claim 18, wherein the method further comprises: providinga wafer and mounting the carrier substrate on the wafer before detachingthe inner area of the thin-film layer from the outer area of thethin-film layer.
 45. The method as claimed in claim 44, wherein theinner area of the thin-film layer is detached from the outer area of thethin-film layer by means of a pick-and-place method.
 46. A method forproducing a thin-film layer, wherein the method comprises: providing acarrier substrate; providing an anti-sticking structure on the carriersubstrate; providing a sacrificial layer on the anti-sticking structureand the carrier substrate; providing the thin-film layer on thesacrificial layer; structuring the thin-film layer in order to obtain ina lateral plane of the thin-film layer an inner area of the thin-filmlayer which is at least partly surrounded by an outer area of thethin-film layer and is arranged in a vertical direction above theanti-sticking structure, wherein during the process of structuring thethin-film layer, at least one opening arises in the thin-film layerwhich at least partially frees the inner of the thin-film layer in thelateral plane, wherein during the process of structuring the thin-filmlayer, at least two webs remain which extend in a lateral plane of thethin-film layer from the outer area of the thin-film layer into theopening in the direction of the inner area of the thin-film layer; atleast partly removing the sacrificial layer proceeding from thethin-film layer in order to eliminate a contact between the inner areaof the thin-film layer and the sacrificial layer, wherein during theprocess of at least partly removing the sacrificial layer, theanti-sticking structure is at least partly exposed.
 47. The method asclaimed in claim 46, wherein the anti-sticking structure compriseselevations extending in at least one lateral dimension along a surfaceof the carrier substrate.
 48. The method as claimed in claim 47, whereinthe elevations have a width of less than 2 μm.
 49. The method as claimedin claim 47, wherein the elevations extend in one lateral dimension,wherein the elevations, in a lateral plane of same, form lines, orwherein the elevations extend in two lateral dimensions, wherein theelevations, in a lateral plane of same, form circles.
 50. The method asclaimed in claim 46, wherein the inner area of the thin-film layercomprises a lattice structure having hexagonal openings, wherein thelattice structure forms a particle barrier, a filter or a membrane. 51.The method as claimed in claim 46, wherein the method further comprises:providing a further anti-sticking structure on an outer area of thethin-film layer or on a layer arranged thereon, providing an at leastsingle-sided-adhesive transfer carrier layer on the inner area of thethin-film layer and the further anti-sticking structure; detaching thetransfer carrier layer in order to detach the inner area of thethin-film layer adhering to the transfer carrier layer from the outerarea of the thin-film layer.
 52. The method as claimed in claim 46,wherein the method further comprises: providing a wafer and mounting thecarrier substrate on the wafer.
 53. The method as claimed in claim 52,wherein the method further comprises: detaching the inner area of thethin-film layer from the outer area of the thin-film layer by means of apick-and-place method.